Spring clamps have been known in the tool industry for quite some time. Spring clamps, of the type to which the present invention is directed, generally are of a plier-like configuration. These clamps are made of multiple stamped metal parts and have a gripping end and handle end with a hinge pin therebetween. The hinge pin acts not only as a fulcrum but also serves to pivotally join together the individual parts of the clamp. A metal spring, usually a torsional helical spring or leaf spring, is secured within the handle end, in cooperation with the hinge pin, to generate the clamping force of the spring. A typical spring clamp of this type is the HARGRAVE.RTM. Spring Clamp manufactured by Warren Tool Corporation, Hiram, Ohio (HARGRAVE is a registered trademark of Warren Tool Corporation.)
These known spring clamps suffer from several inherent problems. To begin with, being made of metal such as steel, the clamps are subject to corrosion in the typical work environment. Furthermore, the multiple piece assembly requires considerable man-hours to assemble the clamp, thereby significantly increasing the cost of the article. Also the relatively thin metal clamp is likely to be permanently, albeit accidentally, deformed in use if it is stepped upon, struck or dropped.
The metal spring clamp is limited in its usage. For example, the metal clamp is not usable with wood, or similar materials, which can be marred by the metal jaws. It is necessary to install suitable jaw inserts or pads on the metal clamps to use them with such material. The metal clamps are not usable with electrical or electronic components as they cause a hazardous risk in shorting the components and shocking the user. Also, the metal clamps are not usable in sterile environments, such as surgical operating rooms and medical laboratories, because they are not easily sterilized. Even if they are sterilized, the metal to metal contact of the clamp parts wear and cause metal deposits to contaminate the otherwise sterile environment.
Efforts to make non-metallic spring clamps have been unsuccessful; and generally have resulted in small clips which do not possess sufficient clamping force to function in the same manner as metal spring clamps. These clips generate merely clamping forces great enough to allow the clip to be attached to an article, such as clips used for identification badges which attach to a person's clothing.
Despite the inherent problems and limitations of prior art spring clamps, and the need for a usable non-metallic spring clamp, none has yet been developed which provides an inexpensive simple construction capable of producing clamping forces equivalent to the clamping forces of metal spring clamps.